Moulsecoomb (/ˈmoʊlzkuːm/) is a suburb of Brighton, Sussex, England, on the north east side around the A270 Lewes Road, between Coldean and Bevendean, 2+1⁄4 miles (3.6 km) north of the seafront. The eastern edge adjoins Falmer Hill on the South Downs. It is often divided into smaller sections on maps: North Moulsecoomb, East Moulsecoomb and South Moulsecoomb.

The name is sometimes pronounced as if spelt Molls-coomb by the locals. It derives from the Old English for Muls Valley. Mul may refer to Mul of Kent, a Saxon nobleman.

Moulsecoomb suffers from high social deprivation and crime rates, along with neighbouring Whitehawk. In 2001, it was in the top 5% of socially deprived areas in England.

Until the First World War the land around the Lewes Road was open downland, sloping towards the valley bottom through which the road and railway line ran. The land reached a height of 508 feet (155m) at Falmer Hill, approximately 0.9 miles (1½ km) east of the point where the railway crossed the road on a viaduct. In the valley bottom, some market gardens and small nurseries were maintained.

The South Moulsecoomb area was developed first: the borough council acquired land at the existing edge of the built-up area, close to the former Preston Barracks on the Lewes Road, in November 1920 and constructed 478 semi-detached houses with large gardens and three bedrooms each. The "Homes fit for Heroes" campaign, started after the war in response to the poor housing conditions faced by returning soldiers, helped to drive this, but the houses were generally too expensive for the families for which they were intended.

The council responded by acquiring more land, including some from the south end of the neighbouring Falmer parish, in 1922; housing areas began to be developed in this area from 1925 onwards. This was the original North Moulsecoomb area, which at this early stage consisted of four roads named after East Sussex villages (Barcombe, Chailey, Newick and Ringmer) situated between the Lewes Road – then an insubstantial, narrow route between the market gardens – and the railway line. By 1929, 390 houses – smaller and more tightly packed than those of South Moulsecoomb – had been built on the 46-acre (190,000 m²) North Moulsecoomb site.

The South Moulsecoomb part of the estate was extended to the east in the early 1930s using land acquired from Lower Bevendean Farm. It is around this area that modern-day Moulsecoomb merges into the Lower Bevendean estate. After this, more land was acquired in December 1935 to extend development at the northern end to the eastern side of the railway. This area is now known as East Moulsecoomb. At first, housing spread northwards from the Higher Bevendean infill estate (an area of private housing developed at the same time as the South Moulsecoomb extension, immediately north of it), with Shortgate Road being the northern limit before the Second World War; after the war, the last few roads were developed, mostly with small blocks of flats. Moulsecoomb Hall on Lewes Road was built as a public hall and community centre in the mid-1930s.

The main purpose of such large-scale residential development was to rehouse residents who lived in slums in central Brighton; at that time, much of the residential accommodation in the inner-city area was of poor quality, and slum clearance would allow redevelopment to start as well as taking people out of inadequate, substandard and sometimes dangerous houses.